The present invention generally relates to a blind fastening system for holding objects onto a modern gypsum wall. It is composed of a self-drilling and slotting fastener nut, a thin retainer cord, and a screw. The fastener nut is inserted through a slotted hole in a surface and held in alignment with the retainer cord for the insertion of a screw for fastening an object onto the surface. The fastener nut has a threaded hole and on the middle of the wide side and an elongated side. The elongated side is a little wider than the width of the threaded hole and has a drilling end. This elongated end is longer than the thickness of the wall and is used to drill a hole through the wall by manually turning the fastener nut. The elongated end also has a serrated side section for making slots on each side of the hole to provide a clean slotted hole in the wall for the full width of the fastener nut.
There are numerous fastening devices that all try to maximize the holding power the fastener exerts onto the back of the surface it is placed onto. The holding power is directly proportional to the amount of surface area that the fastener has on the inside face of the surface. The size of the opening in the surface needed for the insertion of the fastener is another factor in determining the holding power of a fastener. The smaller the hole the less damage the surface has and the stronger the surface is. It is of primary importance that a clean hole be made in the wall for the fastener to achieve maximum holding power. Many products attempt to achieve this, however they quite often fall short.
Some products have a flat wedge shaped fastener being driven through a wall and being used as a fastener. The problem with this device is that the back of the wall gets “blown-out”. That is, the inside portion of the wall gets damaged and does not provide a clean flat surface for the fastener to rest against. In addition to the back surface the material between the front and back face of the wall gets damaged. Another problem is the insertion of the screw through the hole made by the wedge. The width of the screw is usually greater than the width of the wedge and also causes the back of the wall to become “blown-out”. To avoid that, the width of the wedge would have to match the width of the screw, as shown on FIGS. 6 & 7. Having such a wide wedge only compounds the “blow-out” problem.
Other devices show a fastener that makes use of a flexible cord used to align a fastener nut with a matting screw. This type of system requires that a hole be drilled through the wall by a standard tool. The width of the fastener nut is also limited by the size of the hole made in the wall.
The fastening system described in this application maximizes the holding power by having almost the entire flat surface of the fastener against the inside face of the surface.
In addition to having a maximum of holding power and minimum wall damage, the system is simple to use and inexpensive to manufacture.